Furlanetto

My first turbo build and the time to start the car has come; it starts, revs to 1500 and dies almost immediatly. I'm running a p72 with an with a s300 tune for the same motor/injectors from the previous owner of the engine. The only difference is the turbo and routing of charge air piping. I've checked fuel, ignition and mechanical timing. This also occurs when I try to start it with another stock p72 obd2a ecu i have.

Fuel: Getting pressure (35 PSI) to the rail and I removed the rail and checked that injectors fire, pressure is maintained well it's running.

Ignition: Used timing light to check that spark isn't the culprit. It is sparking through until it dies about 2 seconds after the start. Just changed the coil and ignitor thinking they were the issues.

I ran the motor with stock injectors, exhaust manifold and obda p72 ecu to pass emissions about 2 weeks earlier and no problems. The only things i've changed since then is wiring a resistor box, the new injectos, manifold and turbo. Is there any reason the ecu would say "kill fuel"?

Any help would be appreciated.

TravisBiggie

I had the same issue when the tuner changed my base map to a 4 bar map sensor, when I had a 3 bar, I was able to drive it the 5 miles to get it tuned, but constantly died and was hard to drive. not sure if this would be a similar situation for you.

wantboost

iTrader: (2)

It could be a map sensor issue like Travis said.

make sure the map sensor scalar tables in the ecu are set for the map sensor you have now, it could be set up for a different map sensor.

assuming everything on the motor is the same from the previous owner that's the only thing it could be. with a different turbo than what the car was tuned on your tune will be off though.

Furlanetto

Thanks for the quick responses. It was set correctly for the omnibar 4 bar map sensor and the map sensor values displayed on the laptop coincided with the boost gauge. I'm really stumped. Tomorrow I will swap in the stock map sensor and select the stock setting on the smanager and see what happens. The injector size in the smanager is set to 1000cc, i read it has to be a little lower (895cc) in the smanager is this true?

DDTECH

Stock FP is 42. I'd look at the map, see what the overall fuel trim is and offsets are set correctly just because it came from "the same motor setup" doesn't mean the fuel trim is setup for your cranking requirements. Get the car tuned, that's the entire issue.

98vtec

his car isnt your car.

simple resistance differences in wiring circuits can cause differences in the tune.

not to mention those injectors are terrible at idle. they typically like a 12:1-13:1 Idle AFR to be smooth

turbohatch96y7

iTrader: (15)

Which injectors does he have?

I had my car idle fine at 14:1 with 1000cc rc pnh injectors

boostjunkie757

something i noticed...you say the p72 ecu w/ hondata s300 was on the same motor/injectors from the previous owner, and you tried a stock p72 and had the same problem...to me, it sounds like the prior owner of the engine didnt have it boosted, which would be why. just because you have hondata, doesnt mean you have what you need. you need s300b...because it wont run without being able to account for the pressurization of the cylinders.

boostjunkie757

this is exactly what i was referring to. the car was running to pass emissions, then you added the turbocharger afterward and the fuel management isnt set-up for forced induction. you need the s300 with the boost option for this to work.

98vtec

S300 already has built in boost control. you are thinking of s200 which was discontinued a long time ago.

i've tuned several of the larger precision injectors on different engines and they never had good idle quality unless i ran 12:1-13:1

boostjunkie757

really? so s300 can adjust the tune if you throw a turbo on after the tune was programmed on the ecu?


i will admit, i didnt know that s300 didnt need a boost option like s200 did...but even if it is the same ecu and same hondata box, the tune would still need to be adjusted because na and fi are two completely different set-ups..

boostjunkie757

sorry, but my responses might have been a mixture of misinterpreting the original post and not being as familiar with the differences between s200 and s300..

98vtec

http://hondata.com/s300.html

boostjunkie757

ok, so the tune doesnt need to be adjusted after installing a turbo on it? now granted, for all i know the prior owner of the engine did have it boosted also, that information has not been stated, just that the ecu was used on the same engine. so for discussion's sake lets say the prior owner of said engine and ecu was boosted, but lets say when the new owner got it, set it up, installed a different turbo, wouldnt that cause issues that would require tuning also?

turbohatch96y7

iTrader: (15)

Wayyy to much confusing on your part boost junkie.

Yes if you put a different turbo the tune will need to be altered.

If you take a engine and ecu out of one car and put it in another I highly doubt the small resistance differences will throw off the whole tune. Different fuel pressures yes of course will throw off a tune.

People been swapping ecus for years. Never heard of different resistances messing with a car starting.

98vtec

my point is, every car is different and having the engine tuned or at least checked by a tuner is very important.

boostjunkie757

heres what i know..


when you change any variable in any equation, the outcome changes as well.

boostjunkie757

just trying to understand exactly what is going on and provide a little assistance..

in the long run, it isnt my problem.

Furlanetto

The previous owner ran a 3076 motor is dart sleeved with 9:1 built for boost in mind. To avoid confusion a stock obd2a p72 with no s300 was used with stock injectors, map sensor and exhaust manifold in order to pass emissions here in Ontario. Once that was done the whole turbo setup was installed (by me) and now im running the p72 from the previous owner.

So the wideband was indicating that the car was running lean as hell so I turned the "current injector size" down from 1000cc to 600cc and the car idles at 13AFR really smoothly, I drove it down the road to get the exhaust done and any throttle it gets really rich. I understand a tune is needed and it's about an hour drive. I believe the fuel and ignition tables from the previous owner will be okay to get it there, but how do I calibrate the injectors properly? More specifically what dead times and injector voltages should be in the "injector voltage compensation table"?

boostjunkie757

so you used the p72 from the prior owner, that was on an engine that was built with boost in mind, but did not have boost on it....so it was just like i thought...it wasnt tuned with a turbo involved. youve changed the equation and added a variable, which requires tuning because the equation has been altered more than the ecu can account for.

grumblemarc

iTrader: (4)

I thought all that gets done when you get it tuned? Or are you tuning it yourself now?

turbohatch96y7

iTrader: (15)

Stop driving the car and tow it to get it tuned you're going to ruin your motor.

You have no idea what you're doing. Stop installing turbo kits too.

Furlanetto

Okay so I have failed to get the proper information across so here is more detailed info.
The car is a 2000 civic (Canadian si)

I purchased the obd2a p72 ecu to pass emissions with stock injectors, stock exhaust manifold, a 2nd o2 sensor and all evap hooked up on the gsr motor. I just used the obd2a to 2b jumper harness. Anyways I just put that to state that the motor was running fine before this issue. Mechanical timing is good, dizzy is set at 16 before TDC and all the sensors are wired properly.


My setup:
- b18c1 81.5mm dart sleeved block
- cp 9:1 pistons
- supertech springs and retainers
- spoolin performance ramhorn manifold (t3)
- 44mm mvr tial wastegate
- tial q bov
- Mishimotto FMIC with go autoworks 2.5" intercooler piping
- aem rail
- Precision 1000cc low imp injectors
- Performer x intake manifold
- walbro 255
- Precision 5731E mfs T3 Turbo (journal bearing)
- Full 3" back exhaust

The ecu has a tune from the previous owner and here was his setup:
- GT3076r ball bearing turbo
- 3" charge air piping with backdoor vibrant intercooler
- He ran the victor x, I run the performer x (much longer runners)
- Everything else is the same as mine (downpipe, injectors, motor)

He was making 400whp with his setup. So the previous owner was tuned for forced induction with a different turbo and other slight differences as stated above.

My problem: at first I couldn't start, I just changed the injector settings to 600 cc from 1000cc. Now it idles at 13 AFR. I'm not paying $300 to tow it 100km.

I think it may have something to do with the resistor box I installed. I have no idea if the car it was tuned on had a resistor box or not. I custom made my resistor box with a 10ohm resistor in series with each injector (resistors are rated for 10watts).

This is my first build, I've done tons of research, I managed to get it running fine to pass emissions and have confidence that this problem is solvable. Any helpful input would be much appreciated.

Furlanetto

Please ignore the whole obd2 ecu thing, that ecu is no longer relevant to anything in this thread. I just passed emissions with it and immediately after I installed the turbo components. So now I'm running the obd1 p72 with the s300 that I purchased with the motor/injectors/catchcan/ramhorn manifold from the previous owner.

grumblemarc

iTrader: (4)

I wonder what part of "Get it retuned" you're having problems with?